move instance management and firewall help into modal windows

static/style.css

@@ -419,3 +419,76 @@ input:focus {
     margin-top: 1rem;
     font-size: 0.875rem;
 }
+
+/* Modals */
+.modal {
+    display: none;
+    position: fixed;
+    top: 0;
+    left: 0;
+    width: 100%;
+    height: 100%;
+    background-color: rgba(0, 0, 0, 0.7);
+    backdrop-filter: blur(4px);
+    z-index: 2000;
+    justify-content: center;
+    align-items: center;
+    padding: 1rem;
+}
+
+.modal.active {
+    display: flex;
+}
+
+.modal-content {
+    width: 100%;
+    max-width: 500px;
+    margin: 0;
+    position: relative;
+}
+
+.modal-header {
+    display: flex;
+    justify-content: space-between;
+    align-items: center;
+    margin-bottom: 1.5rem;
+}
+
+.modal-header h2 {
+    margin: 0;
+}
+
+.btn-close {
+    background: transparent;
+    border: none;
+    color: var(--text-muted);
+    font-size: 1.5rem;
+    cursor: pointer;
+    line-height: 1;
+}
+
+.btn-close:hover {
+    color: var(--text-main);
+}
+
+.header-actions {
+    display: flex;
+    gap: 0.5rem;
+}
+
+.instances-header {
+    display: flex;
+    justify-content: space-between;
+    align-items: center;
+    margin-bottom: 1.5rem;
+}
+
+.instances-header .actions {
+    display: flex;
+    gap: 0.5rem;
+}
+
+.btn-sm {
+    padding: 0.4rem 0.8rem;
+    font-size: 0.75rem;
+}